1. Field of the Invention
The present invention set forth in this specification pertains to the construction of new and improved motor homes and, more particularly, to the construction of a superstructure platform and the mounting of the platform on a unit chassis. In addition to improving the stability of the vehicle, the present invention also provides rigidity in the motor home, as well as storage space for goods that is easily accessible from the outside of the motor home.
2. Description of Related Art
The term "motor home" is commonly utilized to designate a motor vehicle capable of being utilized as a place of residence. Motor homes are constructed in a variety of sizes and shapes. Motor homes are commonly constructed with conventional motor vehicle parts and components.
Motor homes are normally built on a "chassis" of a motor vehicle. The motor vehicle industry produces various truck-like chassis on which various manufacturers build shell-type enclosures containing simulations of home-living components. These motor homes are powered by a variety of engines located in the front, the rear, or midway in the chassis. As used in this specification, the term "chassis" is employed to designate all of the mechanical components of a motor home produced by the motor vehicle industry. Thus, a "chassis" includes various mechanical components such as the motor, front and rear axles, control pedals, steering wheel and the like, as well as the chassis frame upon which these and other items are mounted. Conventional wheels are attached to the front and rear axles to support the chassis frame. Most commonly, the chassis frame includes two somewhat parallel elongated members which extend between the front and rear ends of the chassis. The chassis frame is normally utilized for the purpose of directly or indirectly supporting the vehicle shell.
As used herein, the term "shell" generally refers to and includes a frame-like structure, including a floor which extends over the chassis in order to surround the usable space within a motor home. The shell is typically supported by the chassis, and encloses both the forward portion of the chassis where various operating controls for the vehicle are located, and the living area which extends from the front portion towards the rear of the vehicle.
As described above, the chassis frame includes two parallel elongated members which extend between the front and rear ends of the chassis, commonly referred to as chassis rails. These chassis rails are normally constructed of steel beams having a channel-shaped cross-section. The chassis rails are spaced apart, with the length of the rails being dependent upon the variations in the wheel bases of different motor vehicles.
Since the floor of the motor home shell is generally built upon the chassis, it is desirable to have the chassis be flat and straight. However, because of the manner in which a vehicle chassis is normally constructed, the twin rails are not sturdy and are subject to bending and twisting moments. For example, the weight of an engine and transmission mounted to the rails at the rear of the vehicle can cause the rails to bow, resulting in the midportion of the chassis rails being up to 11/2 inches higher than the rear portion of the rail. Still further, while being shipped the chassis is often secured to its transport by chains. This manner of securing the chassis often results in the chassis rails being nonplanar, bent, or deformed en route to their destination. As a result, it is not always possible to construct the floor of the motor home shell upon a chassis that is be flat and straight.
Since the shell of the motor home is generally built upon the chassis, it is desirable to have the chassis provide support to the shell. However, as described above, the vehicle chassis rails are not sufficiently sturdy and are further subject to bending and twisting moments from dynamic forces. For example, while the motor home is being driven on the highway, the chassis flexes due to a number of dynamic forces imparted by the various road conditions, especially during cornering or when the motor home is rounding a curve. In an attempt to minimize the dynamic forces acting on the frame, the prior art relies upon a number of compensating devices. These devices include gas pressure shocks, high density bushings, and sway bars to help the vehicle maintain stability and stick to the road, especially during cornering. These devices, however, never fully compensate for the dynamic forces, but instead add more complexity to the vehicle and more mechanisms to maintain. Further, these devices add additional weight to the motor home, both reducing gas milage and reducing the weight which could be otherwise allocated to other more useful items to the motor home's inhabitants.
Still further, the inadequacy of the chassis frame to provide support to the shell often results in the bending and twisting moments being transferred from the chassis to the shell. As a result of this flexing, the sidewalls of a motor home often develop cracks and fractures. In an attempt to minimize the dynamic forces acting on the shell, the prior art relies upon a number of undesirable compensating methods. One method is simply to add extra material to the walls. For example, a solid lattice of tubing and sheet metal can be added. This additional material, however, does not solve the problems which cause the cracking and, instead, simply adds additional weight to the motor home, thus further reducing the weight which could be allocated to other useful items in the motor home. In some instances, this additional weight, added at some distance from the center of gravity of the vehicle, further compounds the poor road handling characteristics described above.
One further disadvantage of current construction of motor home structures is that they often fail to provide adequate, accessible storage space. The lack of storage space results from the current method of construction of motor homes in which the shell floor is mounted directly upon the vehicle chassis. It is desirable to provide space for the storage of the miscellaneous personal goods, such as luggage, tools, fishing rods, folding chairs and so on. Further, it is especially important to provide storage space for various tanks or vessels (fuel, water, LPG) as are needed in connection with the operation of a motor home. Current construction methods provide only limited solutions to the problems of where to position and how to mount these various different vessels and, in particular, where to position such vessels to achieve a satisfactory weight distribution, while maintaining accessibility for easy service.